The present invention relates to an atomizer for coating objects with powder, and particularly to means for producing spiral rotation of the powder being atomized prior to atomizing.
One such device is known from German Patent Application DE-OS No. 30 14 133. It shows means for producing spiral rotation of the particles of the gas-powder mixture, which means include a supplementary gas channel which introduces supplementary gas substantially tangentially into the feed channel of the gas-powder mixture. This causes cyclone-like rotation of the gas-powder mixture, around the central axis of the feed channel which conducts this mixture. That rotation takes place relatively far upstream, for example, in the range between 4 cm and 40 cm, of an atomizer nozzle that is arranged at the end of the feed channel. At this nozzle, spraying of the powder is effected by an atomizing gas, which is introduced substantially tangentially. The atomizer nozzle is an open funnel without baffles, so that atomizing is exclusively caused by the simultaneously action of the atomizer gas and by the diffuser effect of the atomizer nozzle. The cyclone-like flow of the mixture, which is effected relatively far upstream, has the purpose of slowing down the flow of mixture and of displacing the particle concentration of the mixture radially outward where the particles are picked up better by the atomizer air and are atomized in a cloud. At the same time as the flow of the gas-powder mixture in the axial direction of the feed channel is slowed, this assures that no "tongue-like" concentration of particles takes place in the atomized cloud of powder.